Intelectin (H-type lectin) (ITLN)

H-type lectins are a distinct family of carbohydrate-binding proteins characterized by a unique structural fold originally identified in invertebrates like the sea squirt Halocynthia roretzi and the snail Helix pomatia. In humans, the family is represented by Intelectin-1 (also known as Omentin-1) and Intelectin-2, which serve as soluble pattern recognition receptors in the innate immune system. These proteins specifically recognize and bind to microbial glycans, such as D-galactofuranose, which are absent in human cells, allowing for the selective targeting of pathogens. Beyond their immunological role, Intelectin-1 is a major adipokine secreted by visceral adipose tissue that enhances insulin sensitivity and exerts anti-inflammatory and anti-apoptotic effects. In oncology, H-type lectins are highly significant as both biomarkers and therapeutic targets; for instance, Intelectin-1 is a specific marker for malignant pleural mesothelioma and shows prognostic value in colorectal and hepatocellular carcinomas. Currently, research focuses on utilizing recombinant Omentin-1 for metabolic disorders and leveraging the unique carbohydrate-binding properties of the H-type fold for specialized diagnostic imaging and drug delivery systems targeting cancer-associated glycans.

Other names

OmentinOmentin-1ITLN1ITLN2H-type lectinHL-1Intestinal lactoferrin receptorGalactofuranose-binding lectin

Intelectins function as soluble pattern recognition receptors that selectively bind microbial glycans, such as D-galactofuranose, which are not present in mammalian cells, thereby facilitating innate immune responses [1, 5]. In metabolic contexts, the human homolog Omentin-1 (ITLN1) acts as an insulin-sensitizing adipokine that enhances glucose uptake by activating the AMPK and PI3K/Akt signaling pathways in adipose and muscle tissues [3, 4, 6]. Additionally, H-type lectins from invertebrates are utilized in diagnostics to target aberrant GalNAc glycosylation (Tn antigen) on cancer cells [1, 11].